Reversible ratchet



July 23, 1968 L E. KlLNl-:ss 3,393,780

REVERSIBLE RATCHET Filed Jan. 26, 1967 2 Sheets-Sheet 1 July 23, 1968l.. E. KlLNr-:ss

REVERSIBLE RATCHET 2 Sheets-Sheet 2 Filed Jan. 26, 1967 LUTHER E.K/LNESS United States Patent O 3,393,780 REVERSIBLE RATCHET Luther E.Kilness, 211 E. Philadelphia St., Rapid City, S. Dak. 57701Continuation-impart of application Ser. No. 377,029, .lune 22, 1964.This application Jan. 26, 1967, Ser. No. 617,760

Claims. (Cl. 192-43.2)

ABSTRACT OF THE DISCLOSURE The ratchet mechanism here disclosed utilizesa wedgeaction pawl. Detent means act on the pawl for controlling thepawl. One form of the detent means includes a springpressed ball actingon an apex of the pawl. A reversed form of the detent means has a springattached to the pawl acting on detent surfaces in the pawl-carryingbody. An element which acts on the pawl to shift the pawl may act as aguide for orienting the pawl relative to opposing ratchet teeth on atooth-carrying body to assist in proper engagement of the pawl teethwith the opposing ratchet teeth. A manual control which is coaxial withthe toothcarrying body is disclosed for displacing the element acting onthe pawl to shift the pawl.

Cross-references, to related applications This application is acontinuation-in-part of my prior application Ser. No. 377,029, filedJune 22, 1964, and now abandoned, which is a continuation-in-part of myapplication Ser. No. 76,341, tiled Dec. 16, 1960, now abandoned.

Background ofthe invention The invention relates to clutches or ratchetmechanisms in which the engaging element is a wedging pawl. Theinvention has particular application to the ratchet mechanisms used inhand tools, such as ratchet wrenches.

Various control systems have been used for controlling wedge-actionpawls. Examples of some of these control systems can be seen in myUnited States Patents No. 2,554,990, issued May 29, 1951, No. 2,981,389,issued Apr. 25, 1961, No. 3,044,591, issued July 17, 1962, No.3,078,973, issued Feb. 26, 1963, No. 3,265,171, issued Aug. 9, 1966, andNo. 3,269,496, issued Aug. 30, 1966.

The control system which would be used in any application employing awedge-action pawl would depend on the design requirements for t-heratchet mechanism. As applied to ratchet wrenches, particularly wherethe pawl is positioned in a recess at the junction of the handle andhead members, it is advantageous that the pawl controls be -verycompact. This is becoming increasingly important, since the direction ofratchet wrench design is to make the wrench heads as small as possiblein order that the ratchet wrenches may be used in places where space islimited. It is also desirable that the pawl control system have fewparts, which are of simple and rugged construction for longer ratchetlife.

Summary of the invention The invention is a control system for directingwedgeaction pawls. One feature of the invention is detent means which inthe simplest form consists of a spring-pressed ball engaging an apexformed on the back of the pawl. This feature is advantageous where thepawl is positioned at the junction of a wrench head and handle, since ittakes very little space, and the small bore containing the spring andball does not weaken the handle. While this feature may be used incombination with other pawl control elements, it can also be used as thesole ICC element engaging the pawl during the back ratcheting action. Inthis case, the correct placement and angle of the apex on the pawlrelative to the pawl teeth are important to ensure ratcheting action.

Another feature of the invention is a guide for orienting the pawlduring the back ratcheting action of the pawl. This feature enable thepawl to be properly positioned during the important re-engagement partof the ratcheting cycle when all of the pawl teeth are brought into fullengagement for driving. The proper positioning of the pawl preventsmisalignment of the pawl teeth with the opposing ratchet teeth as mayoccur where a large number of teeth are formed on the pawl. Thearrangement of the guide or shift element also permits convenientplacement of the manual control ahead of the pawl, which results in astronger construction for the embodiments having the pawl carried by thehandle since the handle is not weakened by additional bores for themanual control elements behind the pawl recess.

Brief description of the drawing FIGURE 1 is a vertical section of aratchet wrench selected to illustrate the invention.

FIGURE 2 is a partial horizontal section of the ratchet Wrench shown inFIGURE 1.

FIGURE 3 is a horizontal section of a modiiication of the ratchet wrenchshown in FIGURES 1 and 2.

FIGURE 4 is a modification of the invention showing a linear-actionratchet mechanism.

FIGURE 5 is a fragmentary diagrammatic View of a mechanism similar tothose in FIGURES 1, 2, and 3.

FIGURE 6 is a fragmentary Iview of a ratchet mechanism employing aspring-pressed ball element but having the pawl carried by the rotatablemember instead of the handle.

Description ofthe preferred embodiments The ratchet wrench shown inFIGURES 1 and 2 has a body member 10 with a head 11 formed at one end. Arotatable member 12 is journaled in a circular opening 13 in the headfor relative motion with respect to the body member 10. The rotatablemember has a series of radially extending ratchet teeth 14 formed alonga cylindrical portion. A square projection 15 is formed on one end ofthe rotatable member for receiving sockets. A spring-pressed ball 16 onthe projection retains the sockets. A shift cam 17 coaxially positionedwith respect to the rotatable member seals the top of the wrench head. Abottom seal 18 completes the closure 0f the internal ratcheting parts.The bottom seal extends beneath a pawl recess 19 and follows the outlineof the pawl recess. A split-type retaining ring 20 fits in a groove inthe head for maintaining the ybottom seal in assembly. The ends of theretaining ring are accessible at the back of the head 11 and may becompressed to remove the retaining ring.

The pawl recess 19 is positioned opposite to the ratchet teeth 14 andintercepts a portion of the ratchet teeth. The pawl recess has two sidesat the ends of the recess forming bearing surfaces inclined orconverging toward each other in a direction away from the ratchet teeth.A pawl 21 is carried in the pawl recess. The pawl has an arcuate sidehaving a series of teeth 22 adapted to the ratchet teeth 14. All of thepawl teeth are 'used for reversible engagement with the ratchet teeth 14and are brought into full concurrent driving engagement with the ratchetteeth 14 for the forward or driving stroke of the mechanism, which isthat part of the ratcheting cycle Where the mechanism is driving orturning the work. In concurrent driving engagement, all of the pawlteeth are simultaneously in register with or engaged with the ratchetteeth for driving. The arcuate side of the pawl is shorter than thedimension of the pawl recess along the envelope of the ratchet teeth 14,and the other dimensions of the pawl are smaller than comparable recessdimensions to permit circumferential or lateral and radial freedom ofmovement for the pawl. The pawl has sides joining the arcuate side whichare generally inclined or convergent toward each other in a directionaway from the arcuate side. The converging sides of the pawl formbearing surfaces matching the converging sides of the pawl recess fortransmitting the thrust of the pawl to the body mem- `ber for the twodriving directions.

The present invention comprises control means which includes elementsacting between the pawl and the body member 10 that cooperate to urgethe pawl into ratcheting engagement with opposing ratchet teeth. Thecontrol means also includes shift means which comprises elements thatcooperate to shift the pawl from one side of the pawl recess to theother for reversing the ratchet mechanism. The control means includespawl controls having detent means which cooperate Iwithresilientlyacting means for yieldingly urging the pawl toward eitherselected bearing surface of the pawl recess. The detent andresiliently-acting means control system provides an efiicient means forcontrolling a wide-arc pawl of the wedging type and operates with smalllateral movement of the pawl, which is particularly desirable formechanisms having this type of pawl positioned on the handle member. Inaddition, the small space requirements of this control system areimportant since modern ratchet wrench design requires increasinglysmaller wrench heads.

In the embodiment shown in FIGURES l and 2 the resiliently-acting meanscomprises a ball 23. Resilient support for the ball is obtained from aspring 24 contained in a bore 25 in the body member 10. The ball engagestwo detent surfaces on the sides of the V-shaped apex of the pawl formedby the intersection of the straight surfaces ofthe pawl. The ball 23engages one side of the apex lwith the pawl positioned toward one end ofthe recess 19 or toward one bearing surface of the recess and engagesthe other side of the apex with the pawl positioned toward the other endof the recess or toward the other bearing surface of the recess. If theangle of the apex of the pawl is approximately as sharp as shown inFIGURE 2, the ball will exert a force on the pawl tending to keep itagainst a selected bearing surface of the pawl recess and in contactwith the ratchet teeth 14 and causing the pawl to slide over successiveseries of the ratchet teeth 14 during the back stroke.

A shift plate 26 is employed to shift the pawl from one bearing surfaceof the recess 19 to the other. The shift plate is positioned above therotatable member 12 on a concentric hub 27 on the rotatable member. Anextension 28 on the shift plate is entered into a groove 29 on the pawlto connect the shift plate to the pawl. The shift cap 17 is angularlyattached to and positions the shift plate 26 by means of a pin 30 on theshift cap extending into and loosely fitted to a hole 31 in the shiftplate. A friction spring 32 is mounted on the hub 27. The frictionspring is secured to the shift cap by a projection 33 entered into ahole 34 in the shift cap. The friction spring exerts a frictional forceon the hub for yieldingly urging the shift cap to maintain its angularposition relative to the rotatable member 12 after the shift cap ismanually shifted. The loose fit of the pin 30 projecting from the shiftcap into the shift plate 26 affords limited sideways or lateral move.ment of the pawl independently of the shift cap when the pawl engages asuccessive series of the ratchet teeth 14 during the back stroke of thehandle, while the shift cap is urged to subsequently maintain itsangular position relative to the rotatable member 12 because of thefriction spring.

A bar 35 on the shift cap 17 gives manual control of the direction ofratchet driving. With the mechanism adjusted as in FIGURES 1 and 2, theratchet will drive in a clockwise direction. Shifting the bar in aclockwise direction will displace the shift plate 26 and force the pawlto the other bearing surface of the pawl recess against the resistanceof the spring-pressed ball 23 which resists the lateral displacement ofthe detent surfaces on the pawl with respect to itself. The mechanismwill then drive in a counterclockwise direction.

The modification of the invention shown in FIGURE 3 differs from theembodiment shown in FIGURES 1 and 2 chiefly in that aresiliently-'biased shift plate 36 is employed. The shift plate 36 hasan extension 28 having a close sliding fit to a groove on top of thepawl. With a close fit to the pa-wl groove, the extension 2S serves as aguide means to guide or direct the pawl during the back stroke. Pins 37and 38, extending from the shift cap, engage the ends of slots 39 and 40in the shift plate for moving the shift plate when the shift cap isturned to either of two positions. The slots are of greater radialextent than the pins 37 and 38 to permit a slight rocking movement ofthe shift plate rfor aligning the pawl. The center lhole of the shiftplate is larger than the hub 27 to permit the rocking or eccentricmovement of the shift plate. A pin 41 secures a U-shaped spring 42 tothe shift plate. The U-shaped spring alternately engages pins 37 and 38.As shown in FIGURE 3, one end of the U-shaped spring engages pin 37,while the other end of the U-shaped spring is free. With the U-shapedspring in the position shown in FIGURE 3, the shift plate is given aslight deflection downward as the back stroke is made, resulting in aneccentric positioning of the shift plate and causing the pawl, which isguided or directed by the extension 28 on the shift plate, to take aneccentric alignment or orientation relative to the cylindrical envelopeof the ratchet teeth 14 during the back stroke. The eccentric alignmentof the pawl given by the shift plate 36, which is independent of anyalignment given the pawl by the bearing surfaces of the pawl recess,will cause the pawl teeth nearest the operative bearing surface of thepawl recess to go into engagement first with the ratchet teeth 14 priorto the driving portion of the ratcheting cycle or prior to full drivingengagement of the pawl teeth with the ratchet teeth 14; and prevent apossible defective overlap or misalignment of the pawl teeth with theratchet teeth 14 as might otherwise occur when the pawl teeth are forcedinto full engagement with the ratchet teeth 14 Ifor the driving stroke.The resilient biasing of the shift plate does not interfere with theconcentric alignment of the pawl occurring under load conditions wherethe bearing surface of the recess forces the pawl to take an alignmentas shown in FIGURE 3 and brings all of the pawl teeth into drivingengagement with the ratchet teeth 14.

FIGURE 4 sho-ws a modification of the invention as applied to a linearratchet mechanism. The mechanism has a body member 43 and a slidablemember 44, which is positioned in a channel 45 in the body member. Theslidable member has a series of ratchet teeth 46 formed along a straightline. The body member has a pawl recess 47 having inclined bearingsurfaces. A pawl 48 is carried in the pawl recess. The pawl has a linearseries of teeth 49 adapted to engagement with the ratchet teeth 46. Aresiliently-acting means, consisting of a spring 50, is attached to thepawl. The spring 50 has a central section tightly titted or secured in agroove 51 in the pawl. The groove is formed in a raised portion 52 ontop of the pawl. The spring 50 has V-shaped ends, which engage detentsurfaces consisting of duplicates sets of V-shaped indentations 53 in araised portion 54 of body member 43.

With the pawl in the position shown in FIGURE 4, the slidable member 44can move down but is prevented from moving up by the wedging action ofthe pawl. As the slidable member is moved down, the V-shaped ends ofspring 50 tend to ride up the inclined sides of the V-shapedindentations 53. The spring cannot move relative to groove 51 in thepawl, so that the spring ends will then be under compression and cause arestoring force tending to keep the pawl against the upper bearingsurface of the pawl recess. During continued downward movement of theslidable member the pawl will engage successive series of the ratchetteeth 46. For controlling the ratchet direction a shift pin 55 isattached to the pawl. The shift pin passes through an oversized hole 56in the body member 43, which permits freedom of movement for the shiftpin. Moving the pawl with the shift pin causes the spring 50 to engageeither of the two sets of V-shaped indentations 53 to maintain the pawlin position against a selected bearing surface of the pawl recess.

FIGURE 5 is a diagrammatic view of a ratchet mechanism such as shown inFIGURES l, 2, and 3 and illustrates how the pawl is kept in ratchetingengagement by the spring-pressed ball arrangement. The ratchet mechanismshown in FIGURE 5 has a rotatable member 57 provided with ratchet teeth58. A body member 59 is fitted to the cylindrically disposed ratchetteeth 58. A toothed pawl 60 having inclined bearing surfaces iscontained in a recess 61 in the body member which has correspondingbearing surfaces. A ball 62 is urged against the pawl by a spring 63contained in a bore 64 in the body member. The ball exerts a force onthe side of an apex on the pawl which is intermediate the bearingsurfaces of the pawl and directed away from the toothed side of thepawl. This force acting on the pawl is perpendicular to the pawl Surfaceengaged by the ball and passes in a direction shown by the vector A.With the apex of the pawl formed and arranged as shown in FIGURE 5, thevector A is directed at an obtuse angle a to the extreme or end surface81 of the pawl tooth adjacent to the selected operative bearing surfaceof the recess 61. The obtuse angle a should be larger than 90 degreesplus the angle of friction in order that the force exerted by the ballcan overcome the frictional resistance between the ratchet teeth 58 andthe end pawl teeth adjacent the operative bearing surface of the recess.The force acting on the pawl from the ball 62 will then cause the pawlto slide over successive series of the opposing ratchet teeth during theback or nondriving stroke of the body member 59. Under these conditions,the spring-pressed ball may act alone to hold the pawl in releasableratcheting engagement with the ratchet teeth 58 during the back stroke.

FIGURE 6 shows a ratchet mechanism having a springpressed ball controlelement but having the pawl carried by the rotatable member. Theembodiment shown in the fragmentary view of FIGURE 6 has a body member65 provided with ratchet teeth 66. A rotatable member 67 is journaled inthe body member. A pawl 68 is contained in a pawl recess 69 in therotatable member. A ball 70 is urged against an apex on the pawl by aspring 71 positioned in a bore 72. The force acting on the pawl from thespring-pressed ball 70 is in a direction to urge the pawl toward eitherselected end of the pawl recess 69. Pawl springs 73 and 74 alternatelyengage pins 75 and 76 on opposing ends of the pawl. The pawl springs areheld in position by pins 77 and 78 mounted on the rotatable member 67. Ashift element 79 is positioned above the rotatable member and has anextension entered in a groove 80 on the pawl. The shift element may becomparable to shift plate 26 of FIGURE 2 or to shift plate 36 of FIGURE3 where the guide or alignment function is preferred. The spring-pressedball 70 may be used alone where shallow teeth are used in ratchets ofthe type shown in FIGURE 6, or the spring-pressed ball mayadvantageously be employed in conjunction with control elements such aspawl springs 73 and 74. The Pawl springs are spaced so that only onepawl spring engages a pawl pin 75 or 76 for a selected direction ofratchet driving. The forces acting on the pawl from the spring-pressedball and the pawl springs are preferably adjusted to produce a resultantforce of predominantly tangential direction. For reversing the directionof ratchet driving, the shift element 70 is displaced as describedpreviously for shift plates 26 and 36 of FIGURES 2 and 3 respectively tomove the pawl to either end of the pawl recess for engagement withconverging bearing surfaces of the pawl recess.

The embodiments shown and described herein are illustrative of theinvention and may be modied without departing from the invention asdefined in the claims.

I claim:

1. In a ratchet mechanism having the combination of two members adaptedto relative motion with respect to each other, one of said membershaving a series of ratchet teeth, the other of said members having arecess therein positioned opposite said ratchet teeth and interceptingpart of said lratchet teeth, said recess having two bearing surfacesinclined toward each other in a direction away from said ratchet teeth,a pawl carried in said recess, said pawl having a side with a pluralityof teeth adapted to concurrent driving engagement with said ratchetteeth, all of said teeth on the side of the pawl being used for drivingin both directions, said pawl being smaller than the recess to permitlateral movement of said pawl in the recess, said pawl being adapted forengagement with the bearing surfaces of said recess for transmitting thethrust of the pawl to said other member for the two driving directions,and control means for urging the pawl into reversible ratchetingengagement with said ratchet teeth, wherein the improvement comprisesone of said pawl and said other member having two detent surfaces andsaid control means comprising resiliently-acting means positioned on theother of said pawl and said other member, said resiliently-acting meansbeing arranged to act yieldingly on either rselected detent surfaceduring the back stroke of the ratchet mechanismfor yieldingly urging thepawl toward either selected bearing surface of said recess, saidresiliently-acting means being adapted to engage one of said detentsurfaces with the pawl positioned toward one bearing surface of the4recess and engaging the other of `said detent surfaces with the pawlpositioned toward the other bearing surface of said recess, saidresiliently-acting means and said detent surfaces being arranged forlateral displacement with respect to each other on movement of said pawlfrom one bearing surface of the recess to the other, saidresilientlyacting means and said detent surfaces being further arrangedto act on each other for resisting lateral displacement of one to theother, said control means further comprising means engaging the pawl formoving the pawl against the resistance of said resiliently-acting meansfrom one bearing surface of said recess to the other.

2. In a ratchet mechanism having the combination of two members adaptedto relative motion with respect to each other, one of said membershaving a series of ratchet teeth, the other of said members having arecess therein positioned opposite said ratchet teeth and interceptingpart of said ratchet teeth, said recess having opposing ends havingbearing surfaces inclined toward each other in a direction away fromsaid ratchet teeth, a pawl carried in the recess, said pawl having alside with a plurality of teeth adapted to concurrent driving engagementwith said ratchet teeth, all of said teeth on the side of the pawl beingused for driving in both directions, said pawl being smaller than therecess to permit lateral movement of said pawl, Within said recess, saidpawl having two bearing surfaces, the bearing surfaces of said pawlbeing adapted for engagement with the bearing surfaces of said recessfor transmitting the thrust of the pawl to said other member for the twodriving directions, and control means for urging the pawl intoreversible ratcheting engagement with said ratchet teeth, wherein theimprovement comprises said pawl having an apex intermediate said bearingsurfaces of the pawl, the apex of the pawl being directed away from theside of the pawl having a plurality of teeth, and said control meansincluding resiliently-acting means positioned on said other memberadapted to selectively engage the pawl on either side of the apex ofsaid pawl and arranged to provide a force acting in a direction urgingthe pawl toward either selected end of said recess, saidresiliently-acting means being arranged to engage the pawl on one sideof the apex with the pawl positioned toward one end of said recess andengaging the pawl on the other side of the apex with the pawl positionedtoward the other end of said recess.

3. In a ratchet mechanism having the combination of two members adaptedto relative motion with respect to each other, one of said membershaving a series of ratchet teeth, the other of said members having arecess therein positioned opposite said ratchet teeth and interceptingpart of said ratchet teeth, said recess having two bearing surfacesinclined toward each other in a direction away from said ratchet teeth,a pawl carried in said recess, said pawl having a side with a pluralityof teeth adapted to concurrent driving engagement with said ratchetteeth, all of said teeth on the side of the pawl being used for drivingin both directions, said pawl being smaller than the recess to permitlateral movement of said pawl within said recess, said pawl beingadapted for engagement with the bea-ring surfaces of said recess fortransmitting the thrust of the pawl to said other member for the twodriving directions, and control means for urging the pawl intoreversible ratcheting engagement with said ratchet teeth, wherein theimprovement comprises said pawl having two detent surfaces and saidcontrol means including resiliently-acting means cooperable with saiddetent surfaces for yieldably urging the pawl into engagement witheither selected bearing surface of said recess, said resiliently-actingmeans being arranged to engage one of said detent surfaces with the pawlpositioned toward one bearing surface of said recess and engaging theother of said detent surfaces with the pawl positioned toward the otherbearing surface of said recess, said detent surfaces of the pawl beingso formed and arranged that the force acting on the pawl from saidresiliently-acting means is in a direction making an obtuse angle ofsuicient magnitude with the end surface of the pawl tooth adjacent tothe bearing surface of said recess engaged by said pawl so that theresilientlyacting means urges the pawl to slide over said ratchet teethand releasably engage a successive series of ratchet teeth during theback stroke of said other member.

4. In a ratchet mechanism having the combination of a body member with acircular opening, a rotatable member journaled in said opening, saidrotatable member having a cylindrical portion provided with radiallyextending ratchet teeth, said body member having a recess open to saidratchet teeth, a pawl carried in the recess, said pawl being of smallersize than the recess to permit circumferential and radial movement inthe recess, said pawl having an arcuate side provided with teeth adaptedto concurrent and reversible engagement with said ratchet teeth, all ofsaid teeth on the arcuate side of the pawl being used for driving inboth directions, said recess having two sides forming bearing surfacesconverging toward each other in a direction away from said ratchetteeth, said pawl having two converging sides corresponding to thebearing surfaces of the recess for transmitting the thrust of the pawlto the bearing surfaces of the recess for the two directions of driving,and control means for urging the pawl into reversible ratchetingengagement with said ratchet teeth, wherein the improvement comprisessaid control means including guide means engaging the pawl forcontrolling the alignment of the pawl relative to said ratchet teethduring the back stroke, said guide means being arranged to position saidpawl prior to concurrent engagement 0f the pawl teeth with said ratchetteeth for driving so that the pawl teeth nearest the bearing surface ofthe recess receiving the thrust of the pawl enter into engagement withsaid ratchet teeth before the pawl teeth on the other end of the pawlengage said ratchet teeth, said guide means acting on the pawl toprovide alignment independently of any alignment given the pawl by thebearing surface of the recess receiving the thrust of the pawl.

5. In a ratchet mechanism having the combination of a body member havinga head with a circular opening, a rotatable member journaled in saidcircular opening, said rotatable member having a cylindrical portionprovided with radially extending ratchet teeth, said body member havinga recess open to said ratchet teeth, a pawl carried in said recess, saidpawl being of smaller size than the recess to permit circumferential andradial movement in the recess, said pawl having an arcuate side providedwith teeth adapted for concurrent and reversible engagement with saidratchet teeth, all of said teeth on the arcuate side of the pawl beingused for driving in both directions, said recess having two sidesforming bearing surfaces converging toward each other in a directionaway from said ratchet teeth, said pawl having two converging sidescorresponding to the bearing surfaces of the recess for transmitting thethrust of the pawl to the bearing surfaces of the recess for the twodirections of driving, and control means for urging the pawl intoreversible ratcheting engagement with said ratchet teeth, wherein theimprovement comprises said control means including shift meanspositioned above said rotatable member, said shift means extending backfor engagement with the pawl, said shift means being arranged to movesaid pawl from one bearing surface of said recess to the other ondisplacement of said shift means, said shift means including meansadapted for manual control positioned on the head of said body memberfor displacement of said shift means.

References Cited UNITED STATES PATENTS 893,097 7/1908 Reams. 2,943,5237/1960 Gray et al. l92-43.2 X 2,701,977 2/1955 Stone S31-63.2 2,957,37710/1960 Hare 192--43.2 X 3,019,682 2/1962 Hare 192-43 X BENJAMIN W.WYCHE, III, Primary Examiner.

